In the past, transmitters have been connected to various antennas to permit scheduling of variations in antenna characteristics. The interconnections required are complex and expensive, and have generally been realized by means of coaxial cables. These coaxial cables or connectors have been awkward to use and have sometimes required excessive time for each change.
In an attempt to solve the above problems, a number of various switch systems have been developed to provide quick and convenient coupling between a plurality of transmitters and a plurality of field antennas. Generally speaking, the switch systems involve a crosspoint matrix wherein a plurality of input lines are arranged parallel to one another in a given plane, for example; and a plurality of output lines are spaced apart, in another plane, from the input lines, being arranged orthogonally to the input lines to form the matrix.
Thus, it is well known to provided radio frequency switches capable of selectively coupling any one of a plurality of transmitters or receivers to any one of a plurality of antennas. These switch systems must be able to handle relatively large power inputs and loads, provide a high degree of isolation, and be capable of selectively switching from one power input to any one of a plurality of loads quickly and conveniently.
One type of switch system is described in U.S. Pat. No. 3,666,902 (Owen et al.), which issued on May 30, 1972, such system including a plurality of input and output lines arranged in a matrix, and a plurality of rotatable connectors.
Another switch system is disclosed in U.S. Pat. No. 3,873,794 (Owen), which issued on Mar. 25, 1975. This patent discloses a switch system intended for use in a radio frequency spectrum, and relates to the switching of connections between coaxial cables wherein the characteristic impedance of the switch system generally conforms to the corresponding impedance of the connecting coaxial cables. This patent includes a matrix configuration with a rotatable switch means mounted at each crosspoint, mechanical and electrical interlocks to prevent multiple connections to any given input or output line, and grounding means. The matrix is formed of a plurality of interchangeable modules to allow quick and convenient expansion of the matrix.
Other examples of conventional switching system are disclosed in U.S. Pat. Nos. 3,717,736 (Kershner et al.), which issued Feb. 20, 1973, 4,025,746 (Owen), which issued May 24, 1977, 4,201,899 (Owen), which issued May 6, 1980, 3,885,117 (Owen), which issued May 20, 1975, 3,584,172 (Owen), which issued Jun. 8, 1971, 3,500,004 (Kershner et al.), which issued Mar. 10, 1970, and 3,588,390 (Kershner et al.), which issued Jun. 28, 1971; and Canadian Pat. No. 804,169 (Wright et al.), which issued Jan. 14, 1969.
The unique configuration of the coaxial crosspoint switch according to the present invention provides a high isolation modular switch which exhibits the following characteristics, thereby providing substantial commercial advantages over conventional switching system: (1) high isolation between different connecting modes or switch positions, (2) simple modular construction, (3) expandable by columns and rows, (4) fast switching between inputs and outputs, (5) fully interlocked, and (6) rows and columns individually bi-directional, i.e. complete flexibility of routing.
The present invention also provides many additional advantages which shall become apparent as described below.